The number one complication of a joint injury is loss of motion. The loss of motion is often due to an excess production of fibrous tissue within the joint called arthrofibrosis. Arthrofibrosis is both a mechanical and a biological process, which results in loss of motion of a joint.
Synovial cells make up the lining of a joint. These cells are the source of the problem called arthrofibrosis. The synovial cells transform themselves into fibroblasts upon exposure to cytokines and growth factors produced by damaged vascular endothelium. Sudden increases in range of motion produced by intermittent vigorous physical therapy or intra-operative manipulation cause bleeding within the joint further exposing the synovial cells to the cytokines and growth factors which cause arthrofibrosis.
The current methods for gaining range of motion in joints with early or late arthrofibrosis include vigorous physical therapy, specialized splints, continuous passive motion machines and surgical manipulation under anesthesia. Unfortunately, vigorous physical therapy and surgical manipulation under anesthesia have a high failure rate associated with peri-articular bleeding and the resultant progression of arthrofibrosis. Continuous passive motion machines are not effective as they spend most of the time in the middle range of motion of the joint and not focused on stretching at end range of motion.
The current specialized splints include serial casting, Dynasplint and the Joint Active System, on which the invention will provide personal opinions. All of these splints enclose the limb segment proximal and distal to the joint that needs to be stretched. Furthermore, the Dynasplint allows for only a low load stretching process. The Joint Active Systems devices allow for higher loads to be placed at the joint but at the expense of increased pressure at the limb segments proximal and distal to the joint. The loads used by the Joint Active Systems are low in intensity. Serial casting splints are not removable by the patient and have limited adjustability to change the load placed at the joint. Due to the splint design of these devices energy is trapped within the structure of the splints during the stretching process. As a result there is an unpredictable variation in load seen by the joint during the stretching process. This ‘unpredictability’ creates a sense of unease in the patient using the device to gain range of motion. None of these devices produce a load high enough to assure that for every degree the device moves the joint moves the same amount. Finally, none of these devices allow for an instantaneous or quick release of the load applied to the joint.
There is a need to produce an orthotic device for the treatment of arthrofibrosis, which can stretch the joint into full normal end range of motion in a predictable, consistent and reliable fashion. This device should be rigid enough to not allow the storage of energy within its structure. Furthermore, it should be able to produce a load at the joint high enough to assure that for every degree the device moves the joint moves the same amount. Finally, this orthotic device should allow for instantaneous or quick release of the load applied to the joint.